Cable conveyances for transporting people between a station at a relatively high altitude and a station at a lower altitude, e.g. between a hill or mountain station and a station at a lower point, e.g. in a valley, are widely used, for example, at ski slopes and in areas in which the transport of people to a mountain peak, for example, may prove to be advantageous or desirable.
Such cable conveyances generally comprise a transport cable extending endlessly around pulleys or wheels at the upper and lower station, and a plurality of passenger-carrying vehicles which are suspended at spaced locations from the cable.
The "vehicles" or passenger carriers may be of diverse types. For example, they may be cabins, gondolas or cars, capable of carrying a plurality of people. They may be individual seats or chairs capable of carrying one or two passengers or they may simply be T-bars which entrain the carried individuals up a ski slope. For the purposes of this description, the devices which support the people to be transported will be referred to simply as carriers and the mechanisms by which they are held on the cable as suspension devices.
In more general terms, therefore, a cable conveyance can have a mountain station and a valley station, each of which is provided with a wheel or pulley about which the transport cable passes, at least one of these wheels being driven and a plurality of carriers such as cabins or seats having respective suspension devices enabling the carrier to be coupled to the cable and to be decoupled from the cable.
At least one of the stations is provided with a mechanism for decoupling the suspension devices from the cable, for displacing the carrier decoupled from the transport cable in a movement direction corresponding to the direction of travel of the transport cable and for recoupling the carrier to the transport cable. The displacement mechanism for the carrier after it has been decoupled from the cable and before it is recoupled to the cable is intended to reduce the speed of the carrier after decoupling so that passengers can leave the carrier and passengers can mount the carrier, and for accelerating the carrier to the speed of the cable for recoupling.
At the stations of a cable conveyance with carriers which can be decoupled from and recoupled to the cable, such as gondolas or seats, the decoupled carriers must be or should be recoupled to the cable with a uniform spacing.
Generally the spacing is established at the valley station. For this purpose, a displacement mechanism is provided which guides the carriers on a rail outwardly of the pulley or wheel about which the cable passes so that the carriers move along this rail with a uniform spacing from one another.
The carriers suspended from the transport cable are thus decoupled from the cable in the latter station and guided away form the cable on this guide rail. Usually the guide rail is provided with a displacement chain which engages the carriers in the region in which decoupling from the cable is effected, and in the region in which the carrier is recoupled to the cable.
After recoupling of the carrier from the cable, the carrier may be displaced by a plurality of rollers which are driven with peripheral speeds decreasing in the direction of displacement of the carrier so that the speed of the carrier is reduced from the speed of the cable to such a speed that passengers can safely leave the carrier or mount the carrier.
Immediately upstream of the recoupled region, these rollers are driven with progressively increasing peripheral speed so that the speed of the carriers can be increased to the speed of the cable and the carrier speed so matched with the cable speed that the carrier can be effectively recoupled to the cable.
The displacement of the carriers in their decoupled state is effected, as noted, for a chain which can be provided at spacings of 4 to 5 meters with projecting fingers engaging the carriers and moving them along with this predetermined spacing.
To the extent that an oncoming carrier has a different spacing from the preceding carrier, i.e. a spacing less than this predetermined distance at which the carriers are to be recoupled to the cable, the spacing of the carriers before recoupling is corrected by this chain since each carrier is brought to the recoupling region only when it has been engaged by one of the projecting fingers of the displacement chain.
However, should the spacing of the oncoming carriers be greater than the predetermined normal distance, the spacing cannot be corrected by the displacement chain in this manner.
Since nonuniform spacings must be avoided in all cases, it has been suggested to retard the cable in the latter instance. However, the complexity involved in retarding the cable, the costs of the equipment for this purpose and the irregular operation of the cable conveyance which results, all are disadvantageous.
In systems using a displacement chain, moreover, problems are frequently encountered because the fingers can swing out of the path of engagement with the carriers in certain operating conditions so that a finger may not always reliably engage a finger. Since it is desirable to operate the cable and the displacement chain at substantially constant speed, it should be evident that considerable difficulty will be encountered because of the problem that the system described is not adequately able to reduce excessive spacings between carriers should such spacings develop.